4 month old crying

My 3 month old going 4 months old is always crying. Sometimes she will cry when bathe or when we wear clothes that need to go through her head. She cry almost everyday night before sleeping. Quite intensely. Is this normal? Not sure why is she crying. And she can only sleep drink. So at night especially when we need to rock her to sleep and drink she will cry like mad. She sleeps about 18 hrs plus per day. Including night sleep and naps. Not sure if it's normal also?